Treatment of mild persistent asthma by cutaneous electronic stimulation
- 1Dept of Medicine, David Geffen School of Medicine, University of California, Los Angeles, 2Depts of Medicine, Epidemiology and Biostatistics, University of California, San Francisco, CA, USA, and 3Eumedic Ltd, Hungerford, UK.
- C. B. Cooper, Medicine and Physiology, UCLA School of Medicine, 10833 Le Conte Avenue, 37–131 CHS, Los Angeles, CA 90095-1690, USA.
To the Editors:
The Global Initiative for Asthma (GINA) has emphasised the importance of assessing control in response to treatment in grading asthma severity 1. However, many asthma patients are inadequately controlled despite conventional treatment. GINA also recognises a potential role for complementary medicine in asthma management 1. FenzianTM (Eumedic Ltd, Hungerford, UK) is a device that provides low current cutaneous electronic stimulation (CES) and is Food and Drug Administration licensed under the category of minimal risk (Device # 21 FR 882.5890) for biofeedback and treatment of pain. Biofeedback might influence bronchial smooth muscle constriction or perception of asthma control. We examined the hypothesis that CES, added to conventional treatment over 6 weeks, improves asthma control, pulmonary function, symptoms and reliance on rescue bronchodilator therapy in patients with persistent asthma.
In total, 20 subjects were recruited (nine males and 11 females), aged 18–65 yrs with a clinical history of mild-to-moderate persistent asthma for ≥3 months 2 and forced expiratory volume in 1 s (FEV1) between 50% of predicted and the lower limit of normal 3. They reported using short-acting bronchodilator therapy on ≥4 days in 2 weeks. Their treatment regimen was otherwise stable consisting of bronchodilators alone or in combination with inhaled corticosteroids. None had evidence of recent respiratory tract infection. The study was approved by the Institutional Review Board (Human Subjects Protection Committee) of the University of California (Los Angeles, CA, USA) and each subject gave written informed consent.
The design was a single-blind, parallel-group study with two baseline visits, 4 weeks apart to ensure clinical stability. Subjects were randomised 1:1 to active or sham treatment consisting of 14 sessions over 6 weeks using a FenzianTM device or an identical but inactivated device. We endeavoured to eliminate treatment and assessment bias. The study personnel who performed the assessments, including pulmonary function tests and administration of questionnaires, were blinded as to whether the subject received active or sham treatment. The personnel administering the treatments obviously could not be blinded but care was taken to follow similar treatment routines in each group.
Asthma control, symptoms and quality of life were assessed using the Asthma Control Questionnaire (ACQ) 4, Asthma Symptom Utility Index 5, Asthma Quality of Life Questionnaire and Short Form-12 6. Subjects recorded the best of three peak flow measurements twice daily along with symptoms (breathlessness, chest tightness, cough, wheezing) and albuterol use on diary cards (AM-2 Asthma Monitor; Cardinal Health, Yorba Linda, CA, USA). Baseline characteristics were well matched between groups as seen in table 1⇓. Significant differences in physiological measures and questionnaires were not detected between visits 1 and 2 verifying clinical stability.
Changes in key outcome measures with sham and FenzianTM treatments are shown in table 2⇓ and figure 1⇓. With CES we found significant improvements in morning peak flow (from 349 to 360 L·min−1; p = 0.029), morning bronchodilator use (from 0.55 to 0.30 puffs; p<0.001), afternoon bronchodilator use (from 1.06 to 0.48 puffs; p<0.001), and a composite of daily symptoms including breathlessness, chest tightness, cough and wheezing by Likert scales (p<0.001). Breathlessness was also assessed using the dyspnoea index of Mahler et al. 7. Transition dyspnoea index was +1.8 with CES but unchanged with sham treatment. These improvements were accompanied by a significant improvement in asthma control by the ACQ (p = 0.023). Evaluation of the ACQ against GINA and National Institutes of Health (NIH) guidelines determined a cut-off point of 1.50 as identifying patients whose asthma is not well controlled, with a positive predictive value of 0.88 8. Thus both groups of subjects were not well controlled on entry into the current study. Those treated with CES showed an improvement in ACQ score from 1.83 to 1.30, i.e. became well controlled, whereas those receiving sham treatments showed deterioration in ACQ score from 1.69 to 1.84.
Spirometry was performed three times at each visit. There were nonsignificant differences in the changes of FEV1 (102 mL) and forced vital capacity (FVC; 116 mL) between the groups favouring CES. Forced expiratory flow at 25–75% of FVC increased by 0.25 L·s−1 with CES but decreased by 0.18 L·s−1 in controls (p = 0.033).
This sham-controlled study shows proof of concept that CES with FenzianTM might offer a novel alternative to conventional pharmacotherapy in patients with mild persistent asthma and perhaps an adjunct therapy for patients with more severe disease. We found a consistent pattern of improved asthma symptoms, including dyspnoea, and reduced bronchodilator use with small changes in airway function. The mechanism of action remains unknown but biofeedback could induce relaxation of bronchial smooth muscle or changes in the perception of asthma symptoms through central nervous system mechanisms.
Statement of interest
Statements of interest for C.B. Cooper, J.R. Colthurst and E.C. Kleerup and the study itself can be found at www.erj.ersjournals.com/misc/statements.dtl
Acknowledgments
We would like to acknowledge the significant contributions of J. Dermand, the study coordinator, M. Patel who administered the treatments and M. Abrazado who performed the blinded assessments (all Exercise Physiology Research Laboratory, University of California, Los Angeles, CA, USA).
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